Hammer mill



W. A. BATTEY March 7, 1939.

HAMMER MILL 3 Sheets-Sheet l Filed Oct. 30, 1956 Y INVE TOR Q.

W. A. BATTEY March 7, 1939.

HAMMER M I LL Filed OGL 30, 1936 3 Sheets-Sheet 2 /V/r/r lNvEN OR www6,?.

BY LMI E y? R ,NWO

W. A. BATTEY arch 7, 1939.

HAMMER MILL Filed Oct. 30, 1956 3 Sheets-Sheet 3 INVEN R K WM Q. BY

@WM Pw@ ATTORNEYS Patented Mar. 7, 1939 .UNITED STATES PATENT OFFICEHAMMER MILL William A. Battey, Haverford, Pa., assignor to PennsylvaniaCrusher Company, Philadelphia, Pa., a corporation of New YorkApplication October 30, 1936, Serial No. 108,317

Claims. (Cl. 83-11) This invention relates to crushing equipment, thehammer circle about vthe duplex cage. A and more particularly to thatclass of equipment feed chute or hopper 23, through which material knownas hammermills, adapted for crushing or is fed into the chamber, ispositioned centrally at breaking coal, stone and the like. the topbetween breaker plates II and I2 which The principal objects of thisinvention are to slope upwardly to meet the feed chute in a man- 5secure greater capacity or fineness of crushing, ner to form the upperportion of the primary or both, and lower maintenance and power costs.zone.

Related objects are to increase the, length of The breaker plate I3 ispivoted by a mechanism service of the crushing elements, to reduce thecomprising a handwheel 29 mounted on a shaft 10 frequency ofreplacements, and to provide uni- 30 to which is attached a worm 3|. Theworm 10 formity of Wear, automatic resharpening of engages with awormwheel 32 mounted in pivot crushing members and ability to wear outthe pin I5 to swing the breaker plate' I3 when the hammers withoutremoval from the mill for handwheel is turned. A similar handwheelturning. mechanism is provided for lthe opposite breaker There havepreviously been in use hammerplate I4. It is intended that duringoperation of 15 mills comprising a rotating' hammer system the machineone of the pivoted breaker plates withina rigid or unsymmetricallyadjustable pershall be closed and the other open. This relaforate cage,but these hammermills have been tionship is shown in Fig. 2 wherein thecombinasubject to the disadvantages of uneven wear of tion breaker plateand tramp iron deflecto-r I3 is crushing members, resulting in widelyvarying shown closed down and plate I4 raised outwardly 20 cage andhammer circle concentricity, entailing to form a tramp iron deiiector 33which with a wide variations in size and character of product. bottomplate 34 and the outer wall of the frame These disadvantages areovercome and the fOIm a tramp irOIl Docket. The PiVO-t Operating aboveobjects attained by means of this invenmechanisms for plates I3 and I4are mechanition by a symmetrical construction of the prlcallyinterconnected by a sprocket and chain 25 mary and secondary crushingchambers and mechanism 9 to maintain the relationship. Inhammermechanism, and the reversible operation stead of the interconnectingmechanism 9, there thereof. The crushing chambers are arranged may beused if desired, an individual handwheel relative to the hammers so asto perform both mechanism for plate I4 such as is shown for primary andsecondary reductions of the mateplate I3. 30 rial and means is providedfor maintaining ac- The cages or screening sections are formedl bycurate concentricity of cage and hammer circles. a frame of arcuatemembers shown at 20 and 2|,

The invention will be better understood from to which are fastenedlongitudinally extending the following detailed description of aspecific screen bars or plates 22 providing screening 35 embodiment withreference to the accompanying spaces therebetween. The two cages o-rscreen- 35 drawings of which: ing sections are supported at the' bottomon the Fig. 1 is a side sectional View, taken at line I--I, pivot shaftI9 and at their upper ends by racks of Fig. 2, of a machine embodyingthe invention; 35 and 36 attached respectively to pivot pins 31 Fig. 2is a section of a front elevation taken at and 38. The racks 35 and 36are raised or low- I40 line 2-2 of Fig. l; ered by a suitable mechanismoperated by hand- 40 Fig. 3 illustrates a detail of an adjustable Wheels39 and' 40, respectively. For illustration, screening cage; themechanism associated with rack 35 will be Fig. 4 is an elevation view insection, showing described: The handwheel 39 is keyed to a handle theessential elements of another machine emshaft 4I having near its innerend a worm 42.

bodying the invention; and The worm engages a wormwheel 43 keyed to a 45Fig. 5 is a top view, partially in section, of the shaft 44 on which isalso keyed a rack pinion 45 machine of Fig.'4. which raises or lowersthe rack. In this way the The machine of Figs. 1 and 2 comprises asupcages or screening sections can be pivoted inporting and enclosingframe IIl which is suitwardly or outwardly on pivot shaft I 9, tomainably webbed to provide strength and rigidity. tain the desiredconcentricity between the cage Within the upper portion of the frame I0is the and hammer circles. primary crushing chamber formed by fixedsolid There is also provided a screw or hydraulic breaker plates I Iandf I2 near the top, pivoted jack mechanism for raising or lowering thepivot solid breaker plates I3 and I4 hinged on pivot shaft I9. 'I'hebearings for shaft I9 rest at each pins I5 and I6, respectively, andthat portion of end on a stud 5I threaded through a hollow bush- 55 ing50 xed within a wormwheel 52 which is mounted over the stud and restedon a boss 49. The wormwheel 52 associated with each stud 5I is turned bya handwheel 53 which operates through a shaft 54 and worm 55 on awormwheel 56 keyed to a shaft-51, to which is also keyed a pair of worms58. The two worms 58 engage the wormwheels 52 respectively; therebyturning bushings 50, which raises or lowers the pivot shaft I9;

To close oif the space between the upper ends of screening sections I'Iand I8 and the tramp iron pocket or pivoted breaker plate, and also tohold plates I3 and I4 rmly in position when they are closed down,- thereare provided members 66 and 41 pivoted at the ends of the sections I1and I8. These members rest against plates 48 and 34, respectively; andwhen a plate I3 or I8 is closed down the corresponding member 46 or 41is wedged between the plate and the member, as shown at member 46.

The machine is provided with a rotor containing a hammer mechanism asfollows: A shaft 24, mounted at each end in bearings, extends throughthe chamber, as shown; and on this shaft, within the chamber, are placeda number of discs 25 regularly spaced apart by collars 26. These discsand collars are secured to the shaft in any suitable manner. of rods 21(10 in this case) extend longitudinally through suitable holes in thediscs 25 at regularly spaced intervals within the circumference of thesediscs and are fastened in place in a suitable manner. Hammers 28 arepivoted on the rods 21 within the spaces between the adjacent discs 25.I'he position of the hammer mechanism is such as to divide the crushingchamber into a relatively large primary crushing zone between thehammers and breaker plates above the perforate screen sections, and asecondary crushing zone of relatively small cross sections between thehammers and the screens. The rotor is located substantially concentricwith respect to the screening sections and the hammers pass close to thescreens.

The cages or screening sections can be adjusted relative to the hammersby operation of the handwheels 39, 48 and 53. To move the screeningmember closer to the hammers, pivot shaft I9 may be moved upward byhandwhe'el 53 and the upper portions of the screening members are pushedinward by handwheels 39 and 40 to maintain accurately the desiredclearanceV between the two circles.

The arrangement of the racks 35 and 36 operated by handwheels 39 and 40may be modied, if desired. An alternative arrangement is shown in Fig. 3which shows the pivot pins 31 and 38 supported respectively in slots 10and 1I of supporting members 12 and 13, attached to the frame. When thestud I is raised as, for example, by the same mechanism as in Fig. 1,the pins 31 and 38 are forced to slide upwardly and inwardly in theirsupporting slots. The arrangement of the pins and slots may, if desired,be reversed; that is, the slots placed in the screen.- ing members andthe pins on the frame members.

The machine of Figs. 4 and 5 is a modification of the invention usefulfor pulverizing material, in which the pulverized material is clearedfrom the machine by wind sweeping. Imperforate members 88 and 8l areprovided within the frame 19 in place of the perforate screening members20 and 2| of Fig. 2. These imperforate members are preferably providedwith longi-A A number f tudinally extending corrugations 82. but thecorrugations may, if desired, be omitted. The breaker plates 83 and 94are perforated with holes 85 large enough for the finely pulverizedmaterial to pass through. Conduits 86 and 81 extend from the sides ofthe frame, or casing, just above the tramp iron pockets to an air box88, adjoining the casing, which communicates with a fan casing 91containing a fan 89 driven from the hammer shaft. These conduits can beopened or closed asdesired by valves 9| and 92, respectively. 'Ihe airexhausted by the fan is passed through a conduit 93 to a cyclone orother means for separating and collecting the pulverized material in awell-known manner, as indicated in Fig. 5. An air intake 94 is providedat each end of the hopper and is preferably provided with a damperdevice such as the rotary disc damper 95 to regulate the amount of airdrawn into the machine.

In operation of the machine of Figs. 1 and 2, the hammer shaft 24 isrotated in either direction by an external source of power (not shown)When the shaft is to be rotated counter clockwise, as shown by the arrowA in Fig. 2, pivoted plate I3 is placed in the closed position and theplate I4 in the open position, as shown in Fig. 2, and for rotation inthe clockwise direction plate I4 is closed and plate I3 is opened. Therotation of the hammer shaft causes the hammers 28 to throw out radiallyby centrifugal force; and the hammers strike masses of the materialwhich have entered the relatively large primary crushing zone from theoverhead feed chute, impacting them by direct blows against the breakerplates for a primary reduction. The material is then driven into therelatively narrow secondary crushing zone formed between the hammers andcages or screen sections where it is reduced to a higher degree ofneness by impact and crushing pressure against the screen bar edges, orscreen plate perforations. Tramp iron is centrifugally thrown intopocket 33 in the case of counter clockwise rotation, and into the pocketat plate I3 in the case of clockwise rotation. These pockets are emptiedfrom time to time.

The breaking action produces continuous wear on the hammers and also atthe screen bars, and when the hammers are rotated in only one directionthe wear occurs principally at one side of the hammers and bars. Theuseful life of the hammers and bars can therefore be greatly prolongedby frequently reversing the direction of rotation to distribute the wearover both sides thereof. The reversibility is permitted by thesymmetrical construction of the hammers and chamber and the location ofthe feed Chute centrally at the top of the primary crushing chamber, forby reason of this construction the breaking action of the material isthe same for either direction of rotation.

Those pieces of material which are. broken small enough to pass throughthe spaces between the bars pass into the chamber 6I between the cageand the frame I0, from where they drop into Aa suitable. conveyor orreceptacle. Those pieces of the material which are still too large to'pass through the screen remain in the chamber and are impacted andcrushed by the hamrners against the nearer edges 60' of the screen bars(in the case of counter clockwise rotation).

To be most effective in producing a clean breaking these edges 60 shouldbe maintained as sharp as possible. The effect of the continued impactsagainst these edges, however, is to wear them rounded or dull.

During the impacting and crushing action much of the material is driventangentially over the surfaces of the screen bars, thus wearing down thebars and sharpening the further edges '52 of the bars at the same timethat the near edges 60 are being dulled. A similar action occurs at thehammers, of which the nearer edges 65 are worn rounded by the impacts,the ends 63 are worn down by the tangential action and the further edges64 are sharpened.

After the machine has been run in the counterclockwise direction forsome time and the edges 60 and 65 have become dulled, the machine maythen be rotated in the opposite direction to take advantage of thesharpened edges 52 and 64. During this direction of rotation, the edges5I) and 65 become resharpened in the manner described above. Thus thebreaking edges of the machine are self-sharpening by the tangentialaction of the material resulting from the close proximity of the hammersto the screen bars, or plates, and reversing the direction of rotation.

The machine described herein by reason of its symmetrical constructionand overhead feed chute is adapted to reversible operation. Thereversible operation introduces the advantages of wear distribution andself-sharpening, resulting in increased service, reduced frequency ofreplacement of hammers and screen bars and lower maintenance cost.

By this invention there are combined in one unit primary and secondarycrushing zones, providing a double reduction. The primary reduction ispromoted by the dropping of the large entering masses directly into thepath of the hammers where they are struck by the faces and fractured andimpacted through the relatively large primary crushing zone against theimperforate breaker plates. This increases primary impact crushingbetween the hammer and overhanging breaker plates, thereby reducing thepower requirement and the wear on hammers and cage bars. The reductionin the primary zone enables the material to enter the relatively narrowtapering space of the secondary crushing zone between the hammers andthe perforate or imperforate cage members. In this secondary zone thematerial is reduced to the desired fine size by the action between therapidly rotating hammers and cage bar edges or corrugations. Thisarrangement for combined primary and secondary reductions results ingreater output of a given neness or in increased neness with the sameoutput, as compared with prior crushing machines of the hammer type,with inherently smaller cage area.

The use of the duplex cage increases the cage area which inherentlyaffords greater output and/or neness of crushing. Although the cages areshown as occupying somewhat less than a semicircle they can if desiredbe extended well above the center line of the machine to occupy morethan a semicircle.

The mechanism for adjusting the height of shaft I9 and for moving in theupper ends of the screening sections provides a ready means foradjusting the duplex cage relative to the hammers, which adjustmentdetermines the size and uniformity of the product. As the, hammersand/or screen bars or corrugations gradually wear down, increasing thespace between them or making the cages eccentric with reference to thehammers or both, the cage position can be adjusted in this manner tocompensate for the wear and restore the desired concentricity, anduniformity of product.

'I'he construction also provides combination breaker plates and trampiron deflectors, which permit tramp iron pocketsgto be opened on theside opposite that on which the primary reduction is being made.

'I'he operation of the wind swept machine of Figs. 4 and 5 is verysimilar to that of the ma' chine shown in Figs. 1 and 2, the principaldifference being the means for expelling the pulverized material.Material to be pulverized is fed in through the feed hopper and reducedby the hammers as in the machine in Figs. 1 and 2. The imperforatesections 80 and 8l act like the screening sections of Figs. 1 and 2except that no material can be passed through, but instead thepulverized material is carried out of the machine by the wind sweepingproduced by the fan. For this purpose the fan is rotated in thedirection to exhaust the air from` the fan casing 91 in'the directionshown by the arrows. Consequently the incoming air drawn into the millthrough the intake openings 94 becomes laden with the pulverizedmaterial as it passes through the primary and secondary reduction zonesand is then exhausted through the perforations in the deector memberover the open tramp iron pocket and through the conduit leading to theair box and fan. From the fan it is sent to the separator which collectsthe pulverized material. To permit this wind sweeping operation thevalve 92 in the conduit above the trap iron pocket which is open must beopened and the other valve A9| may beclosed.

The references to abrasive action are intended to include impact,shearing, crushing and other effects of forcible contact between thehammers, the screen members and the material whereby the hammers andscreen members are worn away or sharpened.

A reversible hammermill as covered by thev claims is a mill in which thehammers may be rotated in either direction, and the crushing chamber andassociated crushing instrumentalities are symmetrically arranged at bothsides of the Ahammer system to provide substantially similar crushingaction regardless of the direction of rotation of the hammers.

I claim:

1. A hammermill comprising a reversible rotatable hammer system, acrushing chamber symmetrical with said system, receptacles for trampmaterial symmetrically located at opposite sides of the upper part ofthe chamber and breaker plates mounted adjacent the receptacles andadjustable to form closures for said receptacles or to leave saidreceptacles in open operative position, the construction and arrangementbeing such that either breaker plate may be located in closed positionwith the other breaker plate in open position in accordance with thedirection of rotation of the hammer system.

2. A hammermill comprising a crushing chamber and a rotating hammersystem in the chamber, said chamberl including screen members adjacentthe hammer path, a pivotal connection between adjacent margins of thescreen members, means for adjusting said connection radially relative tothe hammer system, and means for adjusting the opposite margins of thescreen membersv about said connection.

3. A hammermill comprising a crushing chamber and a rotating hammersystem in the chamber, said chamber including a pair of oppositelylocated screening members, a single means for adjusting simultaneouslythe lower margins of the effective faces of the screening membersradially toward the axis of the hammer system, and separate means foradjusting the upper margins of the screening members radially towardsaid axis.

4. A reversible hammermiil comprising a housing, a crushing chamberwithin the housing and having a substantially horizontal axis, a systemof hammers in the chamber rotated as a unit around a substantiallyhorizontal axis, means for rotating the hammer system at impact-crushingspeed, a feed inlet located centrally over the hammer system, a separatebreaker plate at one side of the inlet mounted in the housing and spacedfrom the hammer path by a distance greater than the diameter of thelargest piece of material to be crushed, positioned to interceptmaterial from the inlet impacted by the ham- -mers when rotated in onedirection, a separate breaker plate at the other side of the inletmounted in the housing and similarly spaced from the hammer path andpositioned to intercept material from the inlet impacted by the hammerswhen rotated in the other direction, and a discharge outlet for crushedmaterial.

5. A reversible hammermiil comprising a housing, a crushing chamberwithin the housing and having a substantially horizontal axis, a systemof swinging hammers in the chamber maintained in operative position bycentrifugal force and rotated as a unit around a substantiallyhorizontal axis, a primary crushing compartment in the chambersurrounding the upper portion of the hammer system and located above thelevel of the axis of the system, an inlet in the compartment locatedover the hammer system, a separate breaker plate mounted in the housingat one side of the inlet in horizontal alignment with the upper part ofthe hammer path and positioned to intercept material from the inletimpacted by the hammers when rotated in one direction, a separatebreaker plate mounted in the housing at the opposite side of the inletpositioned to intercept material from the inlet impacted by the hammerswhen rotated in the other direction, and an outlet for crushed material.

6. A reversible hammermiil comprising a housing, a crushing chamber, asystem of swinging hammers in the chamber maintained in operativeposition by centrifugal force and rotated as a unit, a feed inletlocated centrally over the hammer system, a separate breaker'plate atone side of the inlet mounted in the housing and spaced from the hammerpath by a distance greater than the diameter ofthe largest piece ofmaterial to be crushed and positioned to intercept material from theinlet impacted by the hammers when rotated in one direction, a separatebreaker plate at the other side of the inlet mounted in the housing,similarly spaced from the hammer path and positioned to interceptmaterial from the inlet impacted by the hammers when rotated in theother direction, and a screen located below the hammer system havingedges extending transversely to the direction of travel of the hammersand positioned to support oversize in the hammer path.

7. A reversible hammermill comprising a housing, a crushing chamber, asystem of swinging hammers in the chamber maintained in operativeposition by centrifugal force and rotated as a unit, a feed inletlocated centrally over the hammer system, a separate breaker plate atone side of the inlet mounted in the housing, spaced from the hammerpath by a distance greater than the diameter of the largest piece ofmaterial to be crushed and positioned to intercept material from theinlet impacted by the hammers when rotated in one direction, a separatebreaker plate at the other side of the inlet mounted in the housing,similarly spaced from the hammer path and positioned to interceptmaterial from the inlet impacted by the hammers when rotated in theother direction, a screen located below the hammer system having edgesextending transversely to the direction of travel of the hammers andpositioned to support oversize' in the hammer path, and means forradially adjusting the screen toward the axis of rotation of the hammersystem to compensate for wear.

8. A hammermiil comprising a crushing chamber, a rotating hammer systemin the chamber, a pair of contiguous screen sections adjacent to thepath of the hammers, pivot means located parallel to the axis of thehammer system connecting the adjacent margins of the screen sections toform a hinge joint, and means for adjusting the pivotal means radiallyrelative to the hammer system Xwhile maintaining said means parallel tothe axis of the system.

9. A reversible hammermill comprising a housing, a crushing chamberwithin the housing and having a substantially horizontal axis, saidcrushing chamber having its' opposite sides symmetrical with relation toa longitudinal vertical plane containing the chamber axis, a system ofpivoted hammers in the chamber rotated as a unit around a substantiallyhorizontal axis paralle] with the axis of said chamber, inlet meansopening through the upper portion of the chamber wall and symmetricallyarranged with reference to said vertical plane containing said axis fo-rintroducing the material to be crushed into the chamber over said hammersystem, means for rotating the hammer system at impact crushing speed ineither direction to initially fracture the material being crushed, abreaker plate forming a wall of said chamber at one side of said lplaneand mounted in the housing and spaced from the hammer path by a distancegreater than the diameter of the largest piece of material to be crushedand acting to intercept material from the feed means impacted by thehammers when rotated in one direction, another breaker plate forming anopposite wall of said chamber and symmetrically mounted at the otherside of said plane with respect to the first mentioned breaker plate andsimilarly spaced from the hammer nath and acting to intercept materialfrom the feed means yimpacted by the hammers when rotated in the otherdirection, and a discharge outlet for the crushed material through thelowerportion of the chamber below both of said breaker plates.

10. A reversible hammermiil as set forth in claim 9 having a primarycrushing zone in which the separate symmetrical breaker plates aremounted and a secondary crushing zone having crushing screens providedwith discharge opening edges generally parallel to said axis of thehammer system and located symmetrically adjacent the lower portion ofthe hammer path in position to provide abrasiveaction between thehammers, bars and interposed material.

WILLIAM A. BATI'EY.

